Danspin: Sindi Lanka

Steam from wood pellets is used to dye yarn

The Estonian factory uses the steam from a Linka wood pellet plant in the process of dyeing yarn.

Danspin is one of the world’s largest manufacturers of yarn for the carpet industry. At their dyeing factory in Estonia, Sindi Lanka, the steam from their wood pellet plant is used in the dyeing process.

Earlier the heat came from two gas boilers, but the opportunity for subsidies for biomass led the company to switch to wood pellets. The fuel was chosen as wood pellets are easily accessible in Estonia.

In addition to the plant, Linka was also tasked with water treatment. The use of a steam boiler demands a maximum amount of oxygen and calcium in the water, to avoid damage to the boiler. At Sindi Lanka they use a combination of river and city water, where a varying quality made treatment necessary.

Instead of using silos to store the wood pellets, a pellet pit with a scraper unit was built. The pellet pit offers a higher security of supply from more suppliers, and is it possible to switch to wood chips in the future.

The plant

In the spring of 2016 Linka delivered a 5,000 kW steam boiler, designed for 10 bars and a maximum steam temperature of 184°C. By installing a PLC control system the plant’s operation is constantly monitored. It’s possible to access the plant through an internet connection, which also allows Linka to offer support through remote access.

The boiler is fed from a 70 m2 scraper system where 11 scrapers move the wood pellets to a sunken auger. From here the pellets are transported to the boiler by augers.

By installing an economizer the heat loss is reduced as extra heat is extracted from the flue gas. This leads to higher efficiencies and heating of the feed water.

An automatic ash removal system transports the ash from the boiler to a 12 m3 ash container, placed outside the building.

Specifications

Customer: Danspin A/S
Location: Sindi, Estonia
Fuel type: Wood pellets
Plant size: 5,000 kW
Plant type: Steam plant
Energy type: Process heating
Year: 2016
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Steam production

7.5 t/h

The production of steam per hour, which is used in the dyeing process.